by Jefferson Graham, USA TODAY

by Jefferson Graham, USA TODAY

LOS ANGELES - There is some good news in the fight against AIDS: The rate of diagnosis for HIV infections has fallen in the United States by a third over the past decade, a study finds.

The report, released Saturday by the Journal of the American Medical Association, can be seen as a sign that the AIDS crisis, which first hit the U.S. in large numbers in the 1980s, is starting to subside.

"It means treatment is working," says Thomas Coates, associate director of the AIDS Institute at UCLA, who wasn't involved with the study by the federal Centers for Disease Control and Prevention. "It means people who are infected are getting into care and not progressing to AIDS."

HIV is the virus that causes AIDS, which destroys the immune system. The World Health Organization estimates that 35 million people globally have the virus, which was once thought to be an immediate killer. But new medicines have been able to keep HIV in check - former sports superstar Earvin "Magic" Johnson announced in 1991 that he was HIV-positive and shows no signs of slowing down.

The report covers the years 2002-2011, when nearly 500,000 patients were diagnosed with HIV. "Statistically significant decreases" in diagnosis rates were found in nearly every demographic group, the study says, with the biggest changes for women and individuals 35-44 years old and persons of multiple races.

The findings show 16 out of every 100,000 people ages 13 and older were newly diagnosed with HIV in 2011, a steady decline from 24 out of 100,000 people in 2002.

There is bad news from the study: Infection rates among presumed gay men didn't trend downward. "Increases were found among certain age groups of men who have sex with men, especially young men," the study says. "Because of delays in diagnosis, temporal trends in diagnoses and variations among groups may reflect earlier changes in HIV incidence."

The study blames unprotected sex as the chief culprit for the increase.

Coates says most of the young men getting infected are African-American. "Access remains a problem," he says. "Even with the Affordable Care Act, this is a population not used to having access to care. We need to make sure health services are available."

Additionally, the study points out that it only reports on people who have taken the time to be diagnosed. "Reports show that many at high risk do not test annually and the overall percentage of youth who had ever tested for HIV during the period of analysis was low compared to other age groups."

The study is based on HIV diagnoses from health departments in 50 states, which get results from medical offices.